Isobutylene-isoprene rubber/layered silicate nanocomposites prepared using latex method: Direct casting versus melt mixing after coagulation

摘要

In this study, polymer nanocomposites of isobutylene-isoprene rubber blended with sodium-montmorillonite were prepared using latex and co-coagulating methods and their influence on thermal, mechanical, and gas barrier if isobutylene-isoprene rubber composites were compared. The dispersion of the layered silicates in the matrix of the obtained nanocomposites was investigated using transmission electron microscopy and X-ray diffraction. The transmission electron microscopy images revealed both partially exfoliated and intercalated structures for the isobutylene-isoprene rubber/montmorillonite nanocomposite prepared using the latex method and a purely intercalated structure for the sample prepared using the co-coagulating method. The surfactant used in the latex method played an important role in determining the interlayer distance within the silicates in the isobutylene-isoprene rubber/montmorillonite composites, in which the interlayer d-spacing in the silicates increased relative to that for the co-coagulating method after the curing process. The tensile and thermal properties of the isobutylene-isoprene rubber/montmorillonite nanocomposites improved with respect to those of the neat isobutylene-isoprene rubber. The tensile strength and decomposition temperature of the isobutylene-isoprene rubber/montmorillonite composites (5 parts per hundred resin (phr) montmorillonite blended with latex) increased by 100% and 20?, respectively. The gas-barrier properties of the obtained composites (10 phr montmorillonite blended with latex) even increased by 60% compared with those of the neat isobutylene-isoprene rubber. For the isobutylene-isoprene rubber/clay composites prepared using the co-coagulating method, an observable improvement of the tensile properties was achieved only if the content of the blended clay was greater than 10 phr.